1. FIELD OF THE INVENTION
The present invention relates to an air conditioning apparatus for a clean room, and more particularly to an air conditioning apparatus for a clean room which prevents contamination caused by chemical leakage in the clean room.
2. DESCRIPTION OF THE RELATED ART
FIG. 1 is a cross-sectional view illustrating an example of a conventional air conditioning apparatus for a clean room. In FIG. 1, a circulating air conditioner 2, such as an air blower, for circulating air is provided adjacent to a clean room 1. The air blown by the circulating air conditioner 2 passes through a supply duct 3 of a duet system and is sent into the clean room 1 as pure, fresh air, after having passed through an air conditioning filter 4. The air having thus passed through the inside of the clean room 1 passes through a grating floor 5, a return opening 6 and a return duct 7 of the duct system for adjusting air quantity, and returns to the air conditioner 2. Thus, the air inside the clean room 1 always circulates in the directions indicated by the arrows in FIG. 1.
Facilities 8 for chemical use may be provided in the clean room, and chemicals and the like are supplied to the facilities 8 for chemical use 8 by means of a chemical supply pipe 9.
In such an air conditioning apparatus for a clean room, when chemicals leak from the chemical supply pipe 9 and the like, chemical mist or gas generated from leaked chemicals 20 may be carried in the air circulating in the clean room 1 and then spread throughout the clean room 1 in a short period of time ranging, for example, from seven or eight seconds to several minutes. Accordingly, problems result from such spreading of chemicals such as when toxic chemicals are being used, and negatively affect the physical health of the worker in the clean room 1. When corrosive chemicals are used, the facilities in the clean room 1 will rust.